Yes I know, that is because Phonak use Bluetooth classic, and older standard with more lag, more battery consumption and less quality but far more compatibility. I heard you can connect a Phonak to pretty much anything Bluetooth capable, even old dumb phones or mp3 players.

I have the Resound Nexia which use Bluetooth LE audio, MFI and ASHA protocol which are supposedly better but you need devices that support them. MFI is for Apple devices and ASHA is Android exclusive. But outside of that you are pretty much screwed. LE Audio and the LC3 codec are here (since several years ago) to fix that but adoption it’s being very slow.

For what I’ve read the distro in which Steam OS is based has already BT LE audio and the LC3 codec support built in but it is up to Valve to implement it at a OS level. One can dream :)